Journal of Agricultural and Veterinary Science Qassim University, Vol. 11, No, 2, pp. 80-94 (July 2018/Dhual-Qidah 1439H) The relationship between blood cytokines concentrations and fertility aspects during natural mastitis in Buffaloes Mohamed Mohsen Mansour 1* ; Moustafa Mohamed Zeitoun 2 1 Department of Animal and Poultry Production, Faculty of Agriculture, Damanhur University, Damanhur, Al-Behirra, Egypt; 2 Department of Animal Production and Breeding, College of Agriculture and Veterinary Medicine, Qassim University, Buriedah, Saudi Arabia. (Received 10/3/2018, accepted for publication on 20/5/2018) Abstract: The present study was performed to monitor the influence of mastitis in its clinical or subclinical signs on peripheral cytokines concentrations such as tumor necrosis factor (TNF-α), interleukins (IL) and interferon (IFN)-γ in blood and their subsequent outcome on buffalo cows fertility. Sixty buffalo cows were divided into three groups {healthy (H), n = 20; subclinical mastitis (SCM), n = 18; and clinical mastitis (CM), n = 22}. Results show that TNF-α level was higher (P<0.05) in CM and SCM compared to H cows starting on day 9 pre-breeding onward. Likewise, IL-6 concentrations were higher ( P<0.05) in CM compared to H cows from day 9 pre- insemination (AI) till day 16 post-AI. Moreover, IL-1β levels were higher ( P<0.05) in CM compared to H cows from day 5 through 25 after AI. Also, IF-γ concentrations were greater (P<0.05) in CM and SCM compared to H cows starting on day 9 through day 1 pre-breeding. Moreover, elevated concentrations of these cytokines were associated with reduced (P<0.05) mean diameters of the pre-ovulatory follicles, estradiol levels, corpora lutea diameters and progesterone concentrations in CM and SCM compared to H buffaloes. Consequently, the conception rate in CM buffalo cows was less (P<0.05) than that in SCM and H counterparts. In summary, mastitis is associated with increased production of cytokines such as TNF-α, IL-6, IL-1β, and IF-γ in blood circulation, which probably play a crucial role in suppression of fertility in buffalo cows. Keywords: Buffalo cows, milk, mastitis, mammary gland, cytokines. Corresponding author. * Mohamed M. Mansour E-mail address: mohamedmohsen79@yahoo.com.